Anti-Treaty commander in the Four Courts, Paddy O’Brien is wounded by shrapnel. Ernie O’Malley assumes command. In the morning there is a truce to remove the wounded. Shortly afterward, a massive explosion destroys the western wing of the Four Courts and the Irish Public Records Office along with it. It is thought to have been caused when fires from the artillery bombardment set off munitions stored there, although Free State troops claim that the building was mined. 20 Free State soldiers are maimed in the blast. O’Malley surrenders the Four Courts when Oscar Traynor sends word that he cannot break through to help them. Members of the IRA Army Executive Liam Mellows, Rory O’Connor, Joe McKelvey and Dick Barret are among the prisoners, but O’Malley himself escapes.